Are you happy? Mark Miodownik, materials scientist

Compost makes me happy. I live on the fifth floor and put my organic waste into a tub on the roof. I'm a British guy: I eat potatoes, so there's loads of potato peel. Pretty soon the tub is full and after a few months it's earth. There are worms. How does that work? The worms need their privacy, so you must keep it covered. All you have to do is wait. If you have potato peel, potato plants grow.

I'm proud of the six potatoes that grow in it. I'll make salade niçoise and drop into conversation, 'These potatoes are from my roof.' For sheer happiness, it's hard to beat compost. Suddenly there are worms, ants, flies, bees, flowers, potato plants. I can create this world on the roof of my flat. It may be no coincidence my surname means 'honey maker'. My ancestral history is imposing itself on me. I may keep bees on the roof soon.

How does all this happen? I am so estranged from the land that I don't know the answers. What's sad is that I know a lot about jet engine alloys. I love materials. I love that a mobile phone's screen is made of liquid crystal. I appreciate the beauty of the coiled double helix of tungsten you find in a lightbulb. Use a magnifying glass and you'll find a wonderfully coiled metal lock of hair. We teach concepts such as relativity and quantum mechanics before we know about soil. You'd have thought you'd have to master the earth first. There is a hole in my education. I'm happy to fix it.